It is known to provide trim panels of the aforementioned type making it possible to display pictograms directly on the skin of the panels, said pictograms indicating certain functions or certain states of the vehicle. “Pictogram” refers to any figurative or symbolic drawing used for communication purposes, including alphanumeric signs.
In such trim panels, the pictogram being backlit, the light passes through the substrate layer of the panel and reaches the translucent skin from underneath.
The smallest flaw in the substrate layer on the path of the light degrades the quality of the lit pictogram, due to the diffusion of the light by that flaw in the substrate layer around the area forming the pictogram. The pictogram becomes blurry and the display is degraded. Such flaws for example include the presence of air bubbles or dust in the light's path.